I have a blocked senders list set up for gmail in my G Suite domain. Included in that list are entire domains. However, I still receive messages that have have email addresses with that domain in the from field. Is there something special that needs to be done to block all senders from a domain?

I am asking as a G Suite Administrator. I want to block a domain from sending emails to my domain using the G Suite Administration app. I am blocking the senders by going to Apps > G Suite > Gmail > Advanced Settings > Blocked senders.